Chtenopteryx sicula(Verany 1851)

Introduction

This is the type species of the genus. The type locality is off Messina, Italy. The type is thought to be at the Museum National d'Histoire Naturelle, Nice (Sweeney and Roper, 1998). We have recently examined two small squids from the Mediterranean Sea that do have the visceral photophore in contrast to the description given by Naef below. As a result, the identity of C. sicula remains uncertain as two species appear to be present in the Mediterranean Sea.

Diagnosis

A Ctenopteryx...

with ocular but without (?) visceral photophores.

with arm suckers in at least 4 series distally.

with club suckers in more than 8 series.

Characteristics

Arms

Formula: 4>3>2>1.

Arms I-III with 2 sucker series proximally becoming at least 4 series distally.

Tentacles

Club without keel or protective membranes (Naef's large specimen was damaged, this character has questionable validity).

Suckers of club in more than 8 series.

Photophores

Large photophore present on ventral surface of eye.

Visceral photophore absent (see illustration below), or present*.

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Figure. Ventral view of the viscera of C. sicula, apparently the same specimen as in the title illustration, showing the absence of a visceral photophore and the presence of the accessory nidamental gland. Drawing modified from Naef, 1921/23b.

Comments

A detailed description of this squid from the Mediterranean has not been published to our knowledge. The description of Pfeffer (1912) was based on squid of 13 mm ML and smaller. Joubin (1900) described a composite of three squid of about 50 mm ML taken from the stomach of a dolphin caught off Corsica. Unfortunately these specimens were in poor condition. Earlier descriptions lacked detail. Naef, 1921-23a, made the most detailed description of this species from squid captured off Naples. The description presented here is based on his account.

*We have examined a specimen of C. sicula from the Mediterranean Sea that has the visceral photophore. There may be two species in the Mediterranean going by the name C. sicula; if so, we don't know which is the true C. sicula.

Nomenclature

Chtenopteryx fimbriatus Appellof, 1890, (from off Messina, Mediterranean Sea) Chtenopteryx cyprinoides Joubin, 1894 (from Corsican waters, Messina, Mediterranean Sea stomach of a dolphin) and Chtenopteryx neuroptera Jatta, 1896 (from off Napels, Mediterranean Sea) are considered synonyms of C. sicula by Pfeffer (1912). We accept this view until it can be established that more than one species of the genus is present in the Mediterranean Sea. Pfeffer (1912) established a new form (Chtenopteryx sicula forma chuni) based on a 7 mm ML squid described by Chun from the Indian Ocean. The distinction was based on developmental differences in fin length compared to Mediterranean specimens at similar sizes.

There is some confusion in the literature over the proper spelling of the species name. The species was originally named as Sepioteuthis sicula but the ending was emended by Pfeffer (1912) to siculuswhen he placed the species in Chtenopteryx. Mike Sweeney checked into this and replies, "...I just had a conversation with Ted Bayer. Verany used siculaas an adjective for the Sepioteuthis of Sicily. Chtenopteryxis feminine and therefore requires the species ending as sicula(not siculus)."

Life History

The paralarval stages are similar to those of other species of Chtenopteryx. Chromatophore differences, if present, have not been identified as yet.

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Figure. Left - Two very young paralarvae, ca. ...mm ML, side view. The circular tentacular clubs have about 20 suckers, irregularly arranged. Two chromatophores are present on each side of the mantle. Middle - A more advanced paralarva, ca ... mm ML, ventral, dorsal and side views. An equatorial circulet of 7 large yellow-brown chromatophores is present on the mantle. Posteriorly the expanded vanes of the gladius are visible in the dorsal view. Right - A even more advanced paralarva, ca. ... mm ML, ventral and dorsal views. Drawings and description of paralarvae paraphrased from Naef, 1921/23a.

Distribution

Vertical distribution

Species of Chtenopteryx are genenerally thought to be deep-living, pelagic squids some of which, at least, undergo twilight migrations to spend the night in near-surface waters (e.g. Young, 1978); data, however, are sparse. The image shows Chtenopteryx cf. sicula. swimming near the ocean floor at approximately 1300 m in the Mediterranean. Note not only the proximity to the ocean floor but the dramatic pigmentation pattern with (1) pigmentation of the fins restricted to its muscular bundles, (2) lateral pigmentation of the third arms and broad patches on arm II (?) and (3) a dark oval patch on the dorsal mantle above the digestive gland (left image). The right image was taken about 30 sec. after the first and chromatophores of the arms have been retracted.

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Chtenopteryx sicula(Verany 1851).
Authored by
Richard E. Young and Michael Vecchione.
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